Actuator and method for manufacturing planar electrode support for actuator

ABSTRACT

An actuator as a drive source of robots and the like is usable for housekeeping assistance, job assistance, and nursing help. The drive source itself is small, light, flexible, and safe. A manufacturing method for a planar electrode support therefor is also described. The actuator has an electrolyte layer in contact with a conductive polymer layer disposed in between a first electrode having the conductive polymer layer attached thereto and opposite second electrode, for deforming the conductive polymer layer by application of electric fields to the electrodes. The first electrode has low rigidity in a longitudinal direction of the conductive polymer layer to facilitate expansion and contraction thereof.

TECHNICAL FIELD

The present invention relates to a flat-plate low-profile actuator thatis applicable to household robots and the like, is deformed byelectrical impulses, and has flexibility and light weight, and to amanufacturing method for a planar electrode support for the flat-platelow-profile actuator.

BACKGROUND ART

Several conventional drive sources are used for joint drive mechanismsof industrial robots including electromagnetic motors, hydraulicactuators, and pneumatic actuators. The joint drive mechanisms usingthese drive sources, which include those using electromagnetic motorsand reduction mechanisms mainly made from metals and those using metalhydraulic/pneumatic cylinders, are themselves made of hard and heavymaterials and are managed and used in specific locations withinfactories.

Drive sources of apparatuses such as robots which are expected tooperate near the presence of human beings for housekeeping assistance,job assistance, and nursing help for elderly and physically-challengedpersons in homes, offices, and hospitals, are required to be small,light, flexible, safe.

Examples of such actuators include a rubber pneumatic actuator havinghigh flexibility among the pneumatic actuators, though this actuatorrequires auxiliary equipment such as compressors and control valves fordriving, which limits weight reduction of the entire system.

Accordingly, an artificial muscle actuator using various kinds ofpolymer materials which have light weight and high flexibility has beenproposed, and its practical application is much desired.

A polymer actuator operated by electric impulses is described in thekeynote speech in Non Patent Document 1 (S G. Wax, R. R. Sands, SmartStructures And Materials 1999: Electroactive Polymer Actuators andDevices, Proc. SPIE, Vol. 3669, pp. 2-10, 1999). A conference concerningresearch in this field is held annually, and active research efforts arebeing made. The research is about polymer actuators, which are made ofpolymer gels, metal composite ion polymers, organic conductive polymers,carbon dispersion conductive polymers, dielectric elastomers, and thelike which are driven by electric impulses. Among these, the conductivepolymers such as the organic conductive polymers and the carbondispersion conductive polymers can be driven at relatively low voltageand generate stress having a capacity larger than living body muscles,and have characteristics such as light weight and flexibility.

As an example of the conductive polymers, Patent Document 1 (JapaneseUnexamined Patent Publication No. H11-169394) discloses an actuatormanufactured by forming metal electrodes on a polyaniline film articlethat is an organic conductive polymer and sandwiching the metalelectrode between solid electrolyte molding objects. While the organicconductive polymers themselves have conductivity and so a voltage can beapplied by using these as electrodes, the metal electrodes are formedfor the purpose of avoiding voltage drop caused by resistance of theconductive polymers. By applying a voltage to between these electrodes,anions in the solid electrolyte molding objects move from the cathode tothe anode, as a result of which the polyanilines in the anodes are dopedwith anions and swell. Contrary to this, the polyanilines in the cathodeare subject to the reverse action, that is, the anions are separatedfrom the polyanilines and the polyanilines shrink. As a result, theactuator composed of the conductive polymer and the polyaniline filmarticle is curved. This is a phenomenon of the thin film article beingdeflected to provide a large displacement, though the deflectionrigidity is too low to produce large forces.

An example of the actuator in which a conductive polymer is not deformedby deflection but deformed by expansion and contraction in itslongitudinal direction, and in which an organic conductive polymer isattached to a metallic coil spring as an electrode is disclosed in NonPatent Document 2 (Gordon G. Wallace etc., Smart Structures AndMaterials 2002: Electroactive Polymer Actuators and Devices, Proc. SPIE,Vol. 4695, pp. 8-16, 2002.). The organic conductive polymer is acylinder shape, resulting in a small effective cross-sectional area forgenerating generative force in a bundle. Further in this example, acylinder-shaped conductive polymer with a coil spring is structured tobe housed in a cylinder-shaped container in order to seal an electricfield liquid, which further decreases the effective cross-sectionalarea. Moreover, a force action portion is structured so as to becombined with a movable pin and a spring, which complicatesmanufacturing.

Moreover, Patent Document 2 (Japanese Unexamined Patent Publication No.H07-83159) and Patent Document 3 (Japanese Unexamined Patent PublicationNo. H06-133922) each disclose an actuator having an electrode formedinto a cylinder shape which performs flexing actions by electricimpulses. In both cases, the actuator is formed into a cylinder shape ora coiled shape with a large thickness, which causes the actuator to havepoor responsivity, to operate only at low speed, and which makes itsmanufacturing difficult.

The term “conductive polymers” is herein used to broadly refer toconductive polymers including an organic conductive polymer in which thepolymer itself has conductivity and a conductive polymer doped withconductive materials such as carbon particles.

DISCLOSURE OF INVENTION Issues to be Solved by the Invention

Several objectives of the present invention are to provide a flat-platelow-profile actuator and a manufacturing method for a planar electrodesupport for the flat-plate low-profile actuator using a conductivepolymer, which is capable of generating large force and operating athigh speed, and which is easy to manufacture and excellent inreliability, for solving the above identified issues.

Means for Solving the Issues

In order to accomplish these objectives, the present invention isstructured as shown below.

According to the present invention, there is provided a flat-platelow-profile actuator, comprising:

a planar conductive polymer layer;

an electrode in contact with the conductive polymer layer;

an opposite electrode opposite to the electrode; and

an electrolyte layer in contact with the conductive polymer layer,disposed in between the electrode and the opposite electrode,

-   -   the electrode being a planar electrode patterned to have at        least one bent portion along a longitudinal direction that is an        expansion and contraction direction of the conductive polymer        layer so that rigidity in the longitudinal direction is low        while rigidity in a width direction almost orthogonal to the        longitudinal direction is high, the conductive polymer layer        being deformed to be swelled and shrunken by application of        electric fields to between both the electrodes.

According to the present invention, there is provided a flat-platelow-profile actuator, comprising:

a planar conductive polymer layer;

an electrode in contact with the conductive polymer layer;

an opposite electrode opposite to the electrode; and

an electrolyte layer in contact with the conductive polymer layer,disposed in between the electrode and the opposite electrode,

-   -   the electrode being a planar electrode patterned to have at        least one bent portion along an output direction of drive force        associated with expansion and contraction of the conductive        polymer layer so that rigidity in the output direction is low        while rigidity in a direction almost orthogonal to the output        direction is high, the conductive polymer layer being deformed        to be swelled and shrunken by application of electric fields to        between both the electrodes so that the drive force is outputted        in the output direction.

According to the present invention, there is provided a manufacturingmethod for a planar electrode support for a flat-plate low-profileactuator, in which the flat-plate low-profile actuator has anelectrolyte layer in contact with a conductive polymer layer disposed inbetween an electrode having the planar conductive polymer layer attachedthereto and an opposite electrode for deforming the conductive polymerlayer to be swelled and shrunken by application of electric fields tobetween both electrodes, and the planar electrode support is composed ofthe conductive polymer layer and the electrodes, comprising:

-   -   patterning a planar electrode as the electrode through etching        or punching to have at least one bent portion along a        longitudinal direction that is an expansion and contraction        direction of the conductive polymer layer so that rigidity in        the longitudinal direction is low while rigidity in a width        direction almost orthogonal to the longitudinal direction is        high; and

in a state that the patterned planar electrode is in contact withanother flat plate, forming the conductive polymer layer on theelectrode by electrolytic polymerization or casting method, and thenremoving the flat plate to manufacture the planar electrode support.

EFFECTS OF THE INVENTION

According to the present invention, it becomes possible to provide theflat-plate low-profile actuator having the electrolyte layer in contactwith the conductive polymer layer and disposed in between the electrodehaving the planar conductive polymer layer attached thereto and theopposite electrode for deforming the conductive polymer layer to beswelled and shrunken by application of electric fields to between bothelectrodes, in which the electrode having the conductive polymer layerattached thereto can be the planar electrode also serving as thesupport, which is patterned (pattern-formed) so that rigidity in thelongitudinal direction that is an expansion and contraction direction ofthe conductive polymer layer (i.e., an output direction of drive forceof the actuator) is low while rigidity in the width direction almostorthogonal to the longitudinal direction is high. Consequently, itbecomes possible to realize an actuator as a drive source of apparatusessuch as the robots, which are expected to operate near the presence ofhuman beings for housekeeping assistance, job assistance, and nursinghelp for elderly and physically-challenged persons in homes, offices,and hospitals, and in which the drive source is small, light, flexible,and safe. It becomes also possible to provide a manufacturing methodfor, as such an actuator, a flat-plate low-profile actuator, as well asa planar electrode support of the flat-plate low-profile actuator, whichis capable of generating large force and operating at high speed andwhich is easy to manufacture and excellent in reliability.

BRIEF DESCRIPTION OF DRAWINGS

These and other aspects and features of the present invention willbecome clear from the following description taken in conjunction withthe preferred embodiments thereof with reference to the accompanyingdrawings, in which:

FIG. 1A is a plane view showing an actuator in one configuration in afirst embodiment of the present invention;

FIG. 1B is a cross sectional view showing the actuator in the oneconfiguration in the first embodiment of the present invention;

FIG. 1C is a plane view showing an actuator in another configuration inthe first embodiment of the present invention;

FIG. 1D is a cross sectional view showing the actuator in the anotherconfiguration in the first embodiment of the present invention;

FIG. 2A is a cross sectional view explaining the operation principle ofthe actuator of the present invention;

FIG. 2B is a cross sectional view explaining the operation principle ofthe actuator of the present invention;

FIG. 2C is a cross sectional view explaining the operation principle ofthe actuator of the present invention;

FIG. 2D is a cross sectional view explaining the operation principle ofthe actuator of the present invention;

FIG. 3A is a plane view showing expansion and contraction operation ofthe actuator in the first embodiment of the present invention;

FIG. 3B is a plane view showing expansion and contraction operation ofan actuator in a schematic configuration in the first embodiment of thepresent invention;

FIG. 3C is a plane view showing expansion and contraction operation ofan actuator in another configuration in the first embodiment of thepresent invention;

FIG. 3D is a plane view showing expansion and contraction operation ofthe actuator in the configuration in FIG. 3C in the first embodiment ofthe present invention;

FIG. 3E is a plane view showing expansion and contraction operation ofan actuator in another configuration in the first embodiment of thepresent invention;

FIG. 3F is a plane view showing expansion and contraction operation ofan actuator in another configuration in the first embodiment of thepresent invention;

FIG. 3G is a plane view showing expansion and contraction operation ofan actuator in another configuration in the first embodiment of thepresent invention;

FIG. 3H is a plane view showing expansion and contraction operation ofan actuator in another configuration in the first embodiment of thepresent invention;

FIG. 4 is a view showing a table of comparison of rigidity between anelectrode having a pattern form in patterning according to the firstembodiment of the present invention and electrodes having other forms;

FIG. 5A is a plane view showing a reference example for explaining theresult of analysis and calculation of a deformed state of the actuatorin the first embodiment of the present invention;

FIG. 5B is a plane view showing the result of analysis and calculationof a deformed state of the actuator in the first embodiment of thepresent invention;

FIG. 5C is a plane view showing a result of analysis and calculation ofthe deformed state of an actuator having an electrode form in (c) ofFIG. 4 for explaining the result of analysis and calculation of adeformed state of the actuator in the first embodiment of the presentinvention;

FIG. 5D is a plane view showing the result of analysis and calculationof a deformed state of an actuator having an electrode form of (d) ofFIG. 4 for explaining the result of analysis and calculation of adeformed state of the actuator in the first embodiment of the presentinvention;

FIG. 5E is a graph showing the relationship between a thickness of aconductive polymer layer and a displacement amount of the actuator ofFIG. 5B in the first embodiment of the present invention when a lengthof the actuator is 8 mm and a film thickness of the electrode of theactuator is changed (5 μm, 10 μm, 20 μm);

FIG. 5F is a graph showing the relationship between a thickness of aconductive polymer layer and a growth rate of a displacement amount(displacement growth rate) of the actuator of FIG. 5B in the firstembodiment of the present invention when a length of the actuator is 8mm and a film thickness of the electrode of the actuator is changed (5μm, 10 μm, 20 μm);

FIG. 5G is a graph showing the result of FIG. 5F by taking thedisplacement growth rate as a vertical axis and a ratio of (thickness ofconductive polymer layer/film thickness of electrode) as a horizontalaxis;

FIG. 6 is a plane view showing an electrode on a flat surface as anexperimental model of the first embodiment of the present invention;

FIG. 7A is a plane view showing an actuator in a second embodiment ofthe present invention;

FIG. 7B is a cross sectional view showing the actuator in the secondembodiment of the present invention;

FIG. 8A is a plane view showing an actuator in another configuration inthe second embodiment of the present invention;

FIG. 8B is a cross sectional view showing the actuator in the anotherconfiguration in the second embodiment of the present invention;

FIG. 9A is a plane view showing an actuator in still anotherconfiguration in the second embodiment of the present invention;

FIG. 9B is a cross sectional view showing an actuator in yet anotherconfiguration in the second embodiment of the present invention;

FIG. 10A is a plane view showing an actuator in a third embodiment ofthe present invention;

FIG. 10B is a cross sectional view showing the actuator in the thirdembodiment of the present invention;

FIG. 11A is a plane view showing an actuator in another configuration inthe third embodiment of the present invention;

FIG. 11B is a cross sectional view showing the actuator in the anotherconfiguration in the third embodiment of the present invention;

FIG. 12A is a plane view showing a planar electrode being supported inthe state of being in close contact with another flat plate in amanufacturing method for a planar electrode support equipped with aconductive polymer in a fourth embodiment of the present invention;

FIG. 12B is a cross sectional view showing the planar electrode beingsupported in the state of being in close contact with the another flatplate in the manufacturing method for a planar electrode supportequipped with a conductive polymer in the fourth embodiment of thepresent invention;

FIG. 12C is a plane view showing the state where the conductive polymerlayer is formed so as to cover most parts of the planar electrode andthe flat plate in the manufacturing method for a planar electrodesupport equipped with a conductive polymer in the fourth embodiment ofthe present invention;

FIG. 12D is a cross sectional view showing the state where theconductive polymer layer is formed so as to cover most parts of theplanar electrode and the flat plate in the manufacturing method for aplanar electrode support equipped with a conductive polymer in thefourth embodiment of the present invention;

FIG. 12E is a plane view showing the state where the flat plate isremoved from the electrode and the conductive polymer layer in themanufacturing method for a planar electrode support equipped with aconductive polymer in the fourth embodiment of the present invention;

FIG. 12F is a cross sectional view showing the state where the flatplate is removed from the electrode and the conductive polymer layer inthe manufacturing method for a planar electrode support equipped with aconductive polymer in the fourth embodiment of the present invention;

FIG. 12G is a cross sectional view showing the state where a conductivepolymer layer is formed also on the back surface of the conductivepolymer layer in the manufacturing method for a planar electrode supportequipped with a conductive polymer in the fourth embodiment of thepresent invention;

FIG. 12H is a plane view showing the state where cutoff portions on bothsides are respectively cut off from the planar electrode in themanufacturing method for a planar electrode support equipped with aconductive polymer in the fourth embodiment of the present invention;

FIG. 12I is a cross sectional view showing the state where cutoffportions on both sides are respectively cut off from the planarelectrode in the manufacturing method for a planar electrode supportequipped with a conductive polymer in the fourth embodiment of thepresent invention;

FIG. 13A is a plane view showing the state where a conductive polymerlayer is formed on a substrate and an electrode sandwiched by aregulating jig for use in the manufacturing method in the fourthembodiment of the present invention;

FIG. 13B is a cross sectional view showing the state where theconductive polymer layer is formed on the substrate and the electrodesandwiched by the regulating jig for use in the manufacturing method inthe fourth embodiment of the present invention;

FIG. 13C is a plane view showing the state where a conductive polymerlayer is formed on the substrate and the electrode sandwiched by aregulating jig with a magnet embedded in a base for use in amanufacturing method in a modified example of the fourth embodiment ofthe present invention;

FIG. 13D is a cross sectional view showing the state where theconductive polymer layer is formed on the substrate and the electrodesandwiched by the regulating jig of FIG. 13C;

FIG. 13E is a partially enlarged view showing a failure which may occurin the case of using the regulating jigs of FIG. 13A and FIG. 13B;

FIG. 13F is a cross sectional view showing the state where the magnetattracts the electrode to the side of the magnet by use of theregulating jigs of FIG. 13D;

FIG. 14A is a side view showing a joint drive mechanism in a non drivestate in a fifth embodiment of the present invention in which theactuator in the embodiment of the present invention being applied to anactuator of a joint drive mechanism; and

FIG. 14B is a side view showing the joint drive mechanism in a drivestate in the fifth embodiment of the present invention in which theactuator in the embodiment of the present invention being applied to theactuator of the joint drive mechanism.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinbelow, the embodiments of the present invention will be describedin detail with reference to the drawings.

Before the embodiments of the present invention will be described indetail, various aspects of the present invention will be describesbelow.

According to a first aspect of the present invention, there is provideda flat-plate low-profile actuator, comprising:

a planar conductive polymer layer;

an electrode in contact with the conductive polymer layer;

an opposite electrode opposite to the electrode; and

an electrolyte layer in contact with the conductive polymer layer,disposed in between the electrode and the opposite electrode,

-   -   the electrode being a planar electrode patterned to have at        least one bent portion along a longitudinal direction that is an        expansion and contraction direction of the conductive polymer        layer so that rigidity in the longitudinal direction is low        while rigidity in a width direction almost orthogonal to the        longitudinal direction is high, the conductive polymer layer        being deformed to be swelled and shrunken by application of        electric fields to between both the electrodes.

According to a second aspect of the present invention, there is providedthe flat-plate low-profile actuator as defined in the first aspect,wherein the electrode is a zigzag-shaped planar electrode having aplurality of bent portions along the longitudinal direction that is theexpansion and contraction direction of the conductive polymer layer.

According to a third aspect of the present invention, there is providedthe flat-plate low-profile actuator as defined in the first or secondaspect, wherein the electrode is a planar electrode comprising: aplurality of band-like portions along the width direction almostorthogonal to the longitudinal direction that is the expansion andcontraction direction of the conductive polymer layer; and link portionsalong the longitudinal direction for linking the adjacent band-likeportions.

According to a fourth aspect of the present invention, there is providedthe flat-plate low-profile actuator as defined in any one of the firstto third aspects, further comprising planar extension portions disposedon both sides of the electrode in the longitudinal direction that is theexpansion and contraction direction of the conductive polymer layer, theplanar extension portions being used as force action portions.

According to a fifth aspect of the present invention, there is providedthe flat-plate low-profile actuator as defined in the fourth aspect,wherein the conductive polymer layer is placed on both front and backsurfaces of the electrode, and a hole is provided on the force actionportion that is the extension portion of the electrode so as to link thefront and back conductive polymer layers for reinforcement.

According to a sixth aspect of the present invention, there is providedthe flat-plate low-profile actuator as defined in any one of the firstto fifth aspects, wherein the electrode and the opposite electrodeplaced on the conductive polymer layer are stacked in such a way as tobe alternately disposed.

According to a seventh aspect of the present invention, there isprovided the flat-plate low-profile actuator as defined in any one ofthe first to sixth aspects, wherein the electrode is a thin plate madeof: metal including gold, platinum, nickel, titanium, and stainlesssteel; alloy thereof; or carbon, or any one of these thin plates coatedwith these material groups or subjected to surface treatment such aschemical oxidation.

According to an eighth aspect of the present invention, there isprovided a flat-plate low-profile actuator as defined in any one of thefirst to seventh aspects, wherein the conductive polymer layer iscomposed of a pi-conjugated polymer with a substrate of polyaniline,polypyrrole, or polythiophene; any one of organic conductive polymerswhich are derivatives thereof; or a carbon dispersion conductive polymersuch as carbon fine particles, carbon nanotubes, and carbon fibers.

According to a ninth aspect of the present invention, there is providedthe flat-plate low-profile actuator as defined in any one of the firstto eighth aspects, wherein the electrolyte layer is a polymer gel or apolymer containing an ionic liquid.

According to a 10th aspect of the present invention, there is providedthe flat-plate low-profile actuator as defined in the first or secondaspect, wherein a ratio of a thickness of the conductive polymer layerto a thickness of the electrode is not more than 3.

According to an 11th aspect of the present invention, there is provideda flat-plate low-profile actuator, comprising:

a planar conductive polymer layer;

an electrode in contact with the conductive polymer layer;

an opposite electrode opposite to the electrode; and

an electrolyte layer in contact with the conductive polymer layer,disposed in between the electrode and the opposite electrode,

-   -   the electrode being a planar electrode patterned to have at        least one bent portion along an output direction of drive force        associated with expansion and contraction of the conductive        polymer layer so that rigidity in the output direction is low        while rigidity in a direction almost orthogonal to the output        direction is high, the conductive polymer layer being deformed        to be swelled and shrunken by application of electric fields to        between both the electrodes so that the drive force is outputted        in the output direction.

According to a 12th aspect of the present invention, there is provided amanufacturing method for a planar electrode support for a flat-platelow-profile actuator, in which the flat-plate low-profile actuator hasan electrolyte layer disposed in between an electrode having a planarconductive polymer layer attached thereto and an opposite electrode inthe state of being in contact with the conductive polymer layer, fordeforming the conductive polymer layer to be swelled and shrunken byapplication of electric fields to between both electrodes, and theplanar electrode support is composed of the conductive polymer layer andthe electrodes, comprising:

-   -   patterning a planar electrode as the electrode through etching        or stamping to have at least one bent portion along a        longitudinal direction that is an expansion and contraction        direction of the conductive polymer layer so that rigidity in        the longitudinal direction is low while rigidity in a width        direction almost orthogonal to the longitudinal direction is        high; and

in a state that the patterned planar electrode is in contact withanother flat plate, forming the conductive polymer layer on theelectrode by electrolytic polymerization or casting and then removingthe flat plate to manufacture the planar electrode support.

According to a 13th aspect of the present invention, there is providedthe manufacturing method for a planar electrode support for a flat-platelow-profile actuator as defined in the 12th aspect, wherein theconductive polymer layer is further formed, by electrolyticpolymerization or casting, on a surface with the flat plate beingremoved to manufacture the planar electrode support.

According to a 14th aspect of the present invention, there is providedthe manufacturing method for a planar electrode support for a flat-platelow-profile actuator as defined in the 12th aspect, wherein in a statethat the planar electrode to make the electrode is linked to a cutoffportion, which will not remain as the electrode, through a cutoffportion link portion, the conductive polymer layer is formed on theelectrode by electrolytic polymerization or casting and then the cutoffportion is removed by cutting at the cutoff portion link portion tomanufacture the planar electrode support.

According to a 15th aspect of the present invention, there is providedthe manufacturing method for a planar electrode support for a flat-platelow-profile actuator as defined in the 12th aspect, wherein the planarelectrode to make the electrode is a magnetic substance, and theelectrode made of the magnetic substance is brought into contact withthe another flat plate through attraction by magnetic force.

Hereinbelow, the embodiments of the present invention will be describedin detail with reference to the drawings.

First Embodiment

FIG. 1A and FIG. 1B are a plane view and a cross sectional view showinga flat-plate low-profile actuator in one configuration in a firstembodiment of the present invention, in which a conductive polymer layer3 and an opposite electrode 2 are disposed on either one side in athickness direction of an electrode 1, e.g., on the lower side. This oneconfiguration is an example of the present invention composed of minimumcomponent members.

FIG. 1C and FIG. 1D are a plane view and a cross sectional view showinga flat-plate low-profile actuator in another configuration in the firstembodiment of the present invention. The configuration in FIG. 1C andFIG. 1D is such that with respect to the electrode 1 in the formerconfiguration in FIG. 1A and FIG. 1B, the conductive polymer layer 3 andthe opposite electrode 2 are disposed symmetrically in upper and lowerpositions along the thickness direction. By applying in-phase voltage totwo electrodes 2 opposite to the electrode 1, the actuator can bedeformed to be expanded and contracted in an expansion and contractiondirection 5. In this structure, since the structure is symmetric in thethickness direction, unnecessary bending deformation due to rigidityimbalance will not occur, and so it becomes possible to effectivelyexpand and contract the actuator in a longitudinal direction of theactuator, in other words, the expansion and contraction direction 5(i.e., an output direction of drive force of the actuator), which makesthe configuration more preferable.

The actuator shown in FIG. 1A and FIG. 1B is composed of a rectangularparallelepiped planar conductive polymer layer 3, an electrode 1 set insuch a way as to be embedded on the upper surface of the conductivepolymer layer 3 in FIG. 1A and made of metal such as stainless steels orthe like and, a rectangular plate-like opposite electrode 2 disposedaway from the electrode 1 so as to be opposed to the electrode 1 andmade of metal such as stainless steels or the like, and an electrolytelayer 4 in between the conductive polymer layer 3 in contact with theelectrode 1 and the opposite electrode 2.

The actuator shown in FIG. 1C and FIG. 1D is composed of a rectangularparallelepiped plate-like conductive polymer layer 3C, an electrode 1set in such a way as to be embedded in a center portion in a thicknessdirection of the conductive polymer layer 3C in FIG. 1D and made ofmetal such as stainless steels or the like, rectangular plate-likeopposite electrodes 2 disposed in upper and lower positions away fromthe electrode 1 so as to be opposed to the electrode 1, and made ofmetal such as stainless steels or the like, and electrolyte layers 4 inbetween respective portions of the conductive polymer layer 3C which arein contact with the electrode 1 in upper and lower positions and therespective opposite electrodes 2. As described before, the formeractuator (FIG. 1A and FIG. 1B) has the opposite electrode 2 disposed ononly one side of the electrode 1, whereas the latter actuator (FIG. 1Cand FIG. 1D) is different from the former in that it has the oppositeelectrodes 2 disposed on both the upper and lower sides of the electrode1.

It is preferable, as one example, to structure a flat-plate low-profileactuator having the conductive polymer layer with a thickness of 80 μmor less and the electrode with a thickness of 5 to 50 μm. If thethickness of the electrode is less than 5 μm, it becomes difficult tofulfill the function as a support, whereas if it is over 50 μm, thenrigidity becomes too large and deformation becomes difficult to achieve,thereby making this thickness undesirable. If the thickness of theconductive polymer layer is over 80 μm, then it becomes difficult forion species which come and go from the front and back sides of theconductive polymer layer to spread to the center of the film, and thisdecreases generated deformation and reduces operation speed, therebymaking this thickness undesirable. Further, as one more preferableexample, it is preferable to structure a flat-plate low-profile actuatorhaving a conductive polymer layer with a thickness of 30 μm or less andan electrode with a thickness of 5 to 10 μm.

The electrodes 1 having the conductive polymer layers 3, 3C attachedthereto in FIG. 1A to FIG. 1D are patterned (pattern-formed) so thatrigidity in the expansion and contraction direction 5 of the conductivepolymer layers 3, 3C (longitudinal direction of the actuator in FIG. 1A)is low to make a planar electrode. The pattern form in patterning of theelectrodes 1 in FIG. 1A to FIG. 1D is such that a number of elongatedrectangular width-direction strip-like patterns 1 a are disposed so asto extend along a width direction (width direction of the actuator)almost orthogonal to the longitudinal direction 5 at constant intervalsin the longitudinal direction 5, and the width-direction strip-likepatterns (one example of the band portions) 1 a, which extend in thelongitudinal direction, are in a rectangular short strip shape, and areadjacent to each other, are respectively linked to link portions 1 b atwidth-direction end portions opposed to each other and are bent at therespective width-direction end portions of the actuator. Thus, when theend portions of the adjacent width-direction strip-like patterns 1 a arelinked through the link portions 1 b, the link portions 1 b are disposedalternately in the longitudinal direction so that the electrode 1constitutes a rough zigzag shape. The rough zigzag shape herein refersto an elongated shape which has at least one notch or space in the widthdirection and which disposed in succession in the longitudinal direction5. If the rough zigzag shape is an uniform pattern, then operationcontrol of the actuator is facilitated. In the spaces formed by theadjacent width-direction strip-like patterns 1 a and the link portions 1b, a part of the conductive polymer layers 3, 3C is entrapped, and inFIG. 1A, the electrode 1 is embedded in the conductive polymer layer 3from the top surface to about half the depth of the conductive polymerlayer 3 so that in FIG. 1A, the upper surfaces of the conductive polymerlayer 3 and the electrode 1 are almost the same. In FIG. 1D, theelectrode 1 is embedded in a first conductive polymer layer 3 b from thetop surface to about half the thickness of the first conductive polymerlayer 3 b, as in FIG. 1A, so that the top surfaces of the firstconductive polymer layer 3 b and the electrode 1 are almost the same. Athin rectangular parallelepiped plate-like second conductive polymerlayer 3 a is disposed on the top surface, as a result of which theelectrode 1 is made to be disposed in a middle portion of the conductivepolymer layer 3C, composed of the first conductive polymer layer 3 b andthe second conductive polymer layer 3 a. In terms of functionality, theconductive polymer layer 3C corresponds to the conductive polymer layer3 in FIG. 1A.

Moreover, on both the ends of the longitudinal direction 5 (in otherwords, an arrow 5 may be an output direction of drive force of theactuator) of each electrode 1 in FIG. 1A to FIG. 1D, rectangularplate-like extension portions 1 c of the electrode 1 provided and eachof the extension portions 1 c functions as a force action portion. Onthe pattern formation side of each force action section 1 c of theelectrode 1, the side being opposite to the edges of the force actionsection, three holes 1 d for reinforcing the link between the electrode1 and the conductive polymer layer 3 are disposed in alignment along thewidth direction in FIG. 1A. Further, a pin hole 1 g for inserting a linkpin 7 into the force action portion is formed in the vicinity of thecenter of each of the extension portions 1 c, so that a hook 6 forclipping the extension portion 1 c and the extension portion 1 c arelinked through the pin 7 inserted into the pin hole 1 g, by which a load8 acting onto each extension portion 1 c is supported. Between theelectrode 1 and the opposite electrode 2, a power source 9 capable ofapplying variable voltages to them is connected via a switch 10. Byturning the switch 10 on, a voltage is applied to both the electrodes 1and 2 so as to expand and contract the conductive polymer layer 3 in thelongitudinal direction 5.

In the case where the conductive polymer layer is an organic conductivepolymer, this expansion and contraction action is generated by theconductive polymer layer 3 being doped with or separated from the ionspecies contained in the electrolyte layer 4. The expansion andcontraction action is caused by changes in bulk of the conductivepolymer layer 3 according to coming and going of the ion species as theion species have a certain level of bulk, changes in conformation of theconductive polymer chain structure of the conductive polymer layer 3associated with oxidation reduction action, and further attributed toelectrostatic repulsion by charges of the same kind injected by voltageapplication. In the case where the conductive polymer layer is a carbondispersion conductive polymer, the expansion and contraction action doesnot accompany the oxidation reduction action, but the deformation isconsidered to be achieved by the coming and going of the ion species andthe electrostatic repulsion by charges of the same kind.

For easy understanding of the operation principle, including causes ofthe deformation mechanism, swell and shrinkage deformation accompaniedby the conductive polymer layer 3 (since the conductive polymer layer 3Coperates in the same way, description is herein given byrepresentatively using the conductive polymer layer 3) being doped withor separated from anions 11 (negative ions) is shown in cross sectionalviews in FIG. 2A, FIG. 2B, FIG. 2C, and FIG. 2D. In some kinds oforganic conductive polymer materials, the primary deformation mechanismis attributed to doping and separation of the anions 11. FIG. 2A shows aswitch-off state in which a voltage is not applied to the electrode.FIG. 2B shows the state in which a positive voltage is applied to theside of the conductive polymer layer 3. The anions 11 uniformly presentin the electrolyte layer 4 when no voltage is applied are pulled to theconductive polymer layer side on the side of the positive electrode (seearrows of the anions 11 in FIG. 2A and FIG. 2B), and go into the insideof the conductive polymer layer 3 from the electrolyte layer 4. Alongwith the oxidation process, the volume of the conductive polymer layer 3swells and so the conductive polymer layer 3 expands in the longitudinaldirection 5 along the inside of the lamination surface of the conductivepolymer layer 3. It is to be noted that FIG. 2B shows the state in whichthe left end of the actuator in the longitudinal direction 5 is securedwhile the right end extends from a reference position R on the right endin the switch-off state. FIG. 2C shows a switch-off state in which avoltage is not applied to the electrode, while FIG. 2D shows the statein which a negative voltage is applied to the conductive polymer layer 3contrary to FIG. 2B. The anions 11 present in the conductive polymerlayer 3 are pulled to the opposite electrode 2 (see arrows of the anions11 in FIG. 2C and FIG. 2D), and go away from the conductive polymerlayer 3 into the electrolyte layer 4. Along with the reduction process,the volume of the conductive polymer layer 3 shrinks and the conductivepolymer layer 3 contracts in the longitudinal direction 5 along theinside of the lamination surface of the conductive polymer layer 3. Itis to be noted that FIG. 2D shows the state in which the left end of theactuator in the longitudinal direction 5 is secured while the right endshrinks from the reference position R on the right end in the switch-offstate. In other materials, the expansion and contraction action may begenerated by the coming and going of cations (positive ions) from and tothe conductive polymer layer 3 or by reciprocal coming and going ofanions and cations. However, description has been limited to themechanism of expansion and contraction action with reference to thecoming and going of the anions for simplification purposes.

With the electrodes 1 being set on the conductive polymer layers 3, 3C,application voltages can be applied instantaneously and uniformly to theconductive polymer layers 3, 3C compared to the case where theelectrodes 1 are not set, so that the doping phenomenon of the ionspecies occurs at high speed, allowing high-speed expansion andcontraction action of the conductive polymer layers 3, 3C. Patterningthe electrode 1 in such a way that rigidity in the longitudinaldirection 5 is low while rigidity in the width direction is high asdescribed above makes it possible to generate large generated distortionwithout blocking the expansion and contraction action of the conductivepolymer layer 3, 3C. It has been found that generating the largegenerated distortion is not only a function in a passive sense of term,that is, to prevent blocking of the expansion and contraction action,but the function also fulfills an effect of actively increasing thegenerated distortion through assignment of anisotropy in rigidity by thepatterned electrode 1. This will be described in detail later withreference to FIG. 5A to FIG. 5D.

Further, structuring the electrode 1 as a plate-like electrode havingthe function as a support makes it easy to handle the conductive polymerlayers 3, 3C which are difficult to handle as individual thin layers.The function as the support herein refers to a function of holding andsupporting the conductive polymer layer by setting a part of therigidity of the planar electrode having the function to be larger thanthe rigidity of the conductive polymer layer. Further, since theelectrode 1 is planar, each component member of the actuator is given aplanar structure, which makes stacking easy. The cross sectional ratioof the conductive polymer layer 3, 3C involving the expansion andcontraction action of the stacked actuator allows employment of such aplanar lamination structure, advantageously allowing for easyenhancement of packing density.

A specific structure for patterning the electrode 1 so as to provide lowrigidity in the longitudinal direction may be obtained by disposing anumber of elongated patterns 1 a in the width direction orthogonal tothe longitudinal direction 5 and linking these patterns 1 a through thelink portions 1 b in a zigzag shape or in a bent state as describedabove. Though the in-phase rigidity of flat plates is extremely high,such patterning allows easy implementation of low rigidity in thelongitudinal direction 5. Such a structure concurrently provides highrigidity in the width direction orthogonal to the longitudinal direction5, and assigns anisotropy in rigidity between the longitudinal directionand the direction orthogonal thereto.

In the first embodiment, providing the extension portion 1 c of theelectrode 1 on both the ends of the longitudinal direction and using theextension portion 1 c as a force action portion makes it possible toform the force action portion, which is an essential element of theactuator, in concurrence with patterning, which yields an actuatorhaving the force action portion in the electrode 1 itself. This bringsabout the advantage that an additional member is not necessary as theforce action portion. Further, since the electrode 1 is a memberdirectly linked to the conductive polymer layer 3, 3C which produce theexpansion and contraction action, it becomes possible to securesufficient strength against the load exerted over the force actionportion.

Providing the holes 1 d on the extension portions of the electrodes 1and filling the holes 1 d with the conductive polymers of the conductivepolymer layers 3, 3C make it possible to generate anchor effect, and theanchor effect allows for increasing the strength of the hole portions.While there may be cases where the bond strength in the interfacebetween the electrode 1 and the conductive polymer layers 3, 3C is notnecessarily strong depending on the combination of materials, settingsuch holes 1 d to be filled with the conductive polymers allows the bondstrength in the interface between the electrodes 1 and the conductivepolymer layers 3, 3C to be reinforced.

FIG. 3A to FIG. 3H are plane views showing the expansion and contractionoperation of the actuator in the first embodiment. For simplification,only the conductive polymer layer 3 and the electrode 1 with theconductive polymer layer 3 attached thereto are schematically shown,since the conductive polymer layer 3C operates in the same way,description is given by representatively using the conductive polymerlayer 3 in FIG. 3A to FIG. 3H. A few other configurations adoptable forthe actuator of the present invention will be shown together. FIG. 3Aand FIG. 3B show the case where the form of the electrode 1 is identicalto the pattern form shown in FIG. 1A to FIG. 1D. FIG. 3A shows aninitial state, and FIG. 3B shows the state in which only the left end ofthe actuator in the longitudinal direction 5 is secured while the rightend of the conductive polymer layer 3 expands by δ₁ from a referenceposition R in the initial state in FIG. 3A. More particularly, it isshown that the respective elongated patterns 1 a of the electrode 1deform in the width direction orthogonal to the longitudinal direction 5along the longitudinal direction 5 according to the expansion.

Similarly, as another configuration of the present invention, FIG. 3Cand FIG. 3D show the states before and after deformation in the casewhere the pattern form is constituted by an elongated pattern 1 a of onecycle out of a number of elongated patterns 1 a of the electrode 1. Moreparticularly, it is shown the state in which the left end of theactuator in the longitudinal direction 5 is secured while the right endof the conductive polymer layer expands by δ₂ from the referenceposition R in the initial state in FIG. 3C.

Generally, a large deformation of the actuator can be achieved bysetting the expansion and contraction direction 5 of the actuator as thelongitudinal direction of the actuator, the length of the expansion andcontraction portion thereby being longer. As shown in this example, itis also possible to set the width direction orthogonal to the expansionand contraction direction 5 as the longitudinal direction. The presentinvention is not intended to limit the expansion and contractiondirection 5 of the actuator to the longitudinal direction of theactuator.

Further, as still another configuration of the present invention, FIG.3E and FIG. 3F show a minimum available unit of the pattern form inpatterning of the actuator in the present invention. More particularly,FIG. 3E shows the case where the pattern form is constituted of anelongated pattern 1 a of a half cycle out of a number of elongatedpatterns 1 a of the electrode 1, and FIG. 3F shows the case where thepattern form is constituted of an elongated pattern 1 a of a quartercycle out of a number of elongated patterns 1 a of the electrode 1.

Further, as another configuration of the present invention, thearrangement relationship between the electrode 1 and the conductivepolymer layer 3 in the width direction may be arranged such that thewidth of the electrode 1 is larger than the width of the conductivepolymer layer 3 as shown in FIG. 3G, and the arrangement relationshipmay also be reversed as shown in FIG. 3H. Each case is within the scopeof the present invention.

FIG. 4 is a table showing the result of a calculation to obtain how therigidity in the longitudinal direction can be lowered by the patternforms in patterning of the electrode 1 of the actuator in the firstembodiment of the present invention. Assumed values for the calculationare set as follows: the material is stainless steel SUS304; thelongitudinal elastic modulus is 0.072×10¹²N/m²; and the plate thicknessis 10 μm. In the case of a flat plate (solid state or blockconfiguration) electrode shown in the column (a) in the table, when theupper end of the flat plate with a thickness of 14 mm× a length of 8 mmwas constrained and a distributed load having a total load of 1 mN wasapplied onto the lower end of the flat plate, the displacement in themiddle of the lower end was 0.308 μm. In the case of the pattern formwith a total width 14 mm× a length of 8 mm obtained in patterning theelectrode 1 in the first embodiment of the present invention in column(b) shown in the table, when a concentrated load of the same 1 mN wasapplied to the pattern form in patterning with a line width of 0.1 mmand a pitch of 1 mm and, the displacement in the lower end portion wascalculated at 50.56 mm, and assuming that a rigidity ratio of the formerflat plate is 1, a rigidity ratio of the latter electrode 1 to theformer flat plate is 6.1×10⁻⁶. Thus, patterning of the electrode 1 inthe first embodiment of the present invention makes it possible toreduce the rigidity to 1/100,000 or lower as compared with that in theflat plate.

The column (c) in the table shows, for comparison, the result ofcalculation in the case where the link portions 1 b for linking theelongated patterns 1 a of the electrode 1 are not disposed in the bentstate but are disposed in the center portion of the width of theelongated patterns 1 a and are disposed in succession in thelongitudinal direction. The displacement in the middle portion of thelower end when a concentrated load of the same 1 mN is applied onto thelower end was calculated at 38.6 μm. The rigidity ratio was 7.9×10⁻³,and the rigidity was reduced to at best nearly 1/100. Thus, forachieving a large rigidity reduction effect, it is necessary to disposethe link portions 1 b in the bent state with respect to the elongatedpatterns 1 a of the electrode 1. Further, the column (d) in the tableshows the result of calculation in the case where the electrode ispatterned in a waveform, and the result indicates that such a form canachieve considerable reduction in rigidity.

FIG. 5B to FIG. 5D are views in which conductive polymer layers areattached to the electrodes with the pattern forms in patterning of (b)to (d) shown in FIG. 4, and deformations associated with constriction ofthe conductive polymer layers in in-plane directions aresimulation-calculated by finite element method. Under the conditionsthat the material of the conductive polymer layers is polypyrrole, thelongitudinal elastic modulus is 0.003×10¹²N/m², Poisson's ratio is 0.3,and the conductive polymer layers are to contract in the in-planedirection of the polypyrrole in an isotropic way, deformations in thepattern forms in respective electrode patternings were relativelycompared. The total size was set at 14 mm wide×8 mm long as was the casewith FIG. 4, and the thickness of the polypyrrole conductive polymerlayers was set at 20 μm.

FIG. 5A shows the case in which an electrode is not present and only aconductive polymer layer sheet is present. With the displacement in thecenter portion on the lower end in this case being 1, relativedisplacements at the same location were compared. It is to be noted thatthe results of calculation show the relative displacements, togetherwith the forms before and after the deformations, as well as contourlines showing displacements of respective parts from a constraint point(center on the upper end) in gray scale.

FIG. 5B shows the case in which the conductive polymer layer 3 isattached to the electrode 1 with the pattern form in patterning in thefirst embodiment of the present invention in the column (b) in FIG. 4.The relative displacement in this case was calculated at 1.16,indicating that not only the displacement of the electrode was lessinhibited by reduction in rigidity in the longitudinal direction 5 ofthe actuator, but also such the anisotropy in rigidity of the electrode1 has an effect of increasing the generated displacement. It is to benoted that in FIG. 5B, the state before deformation is shown by a chainline while the shrunken state after deformation is shown by a solidline.

Such a generated displacement increase effect in the longitudinaldirection of the actuator in the present invention may be construed insuch a way that high rigidity in the width direction orthogonal to thelongitudinal direction constrains the displacement in this direction,and distortion components unable to escape will turn out to join thedisplacement in the longitudinal direction of the actuator.

It is to be noted that while it is not strictly affirmed that theconditions used as the assumptions for calculation such as thecontraction being generated in the sheet-plane of the conductive polymerlayer in an isotropic way and the Poisson's ratio being constant arecorrect, the assumption for calculation that the elastic characteristicsof the conductive polymer layer are maintained is considered to be anaccurate approximation.

FIG. 5C shows the case in which the conductive polymer layer sheet isattached to the electrode 1 in the column (c) in FIG. 4 having the linkportions 1 b of the elongated patterns 1 a of the electrode 1 beingdisposed at the middle portions in succession in the longitudinaldirection. In this case, the calculation result indicated that thegenerated displacement increase effect was not realized and that thedisplacement was reduced to 62% of the displacement gained in the caseof the conductive polymer layer sheet only.

FIG. 5D shows the case of the electrode in the column (d) in FIG. 4,which is patterned in a waveform. In this case, the displacementincrease effect, though smaller than that in the case of FIG. 5B, wasrealized. However, while deformation in the case of FIG. 5B is generatedevenly in each part on the entire area, the deformation in the case of Dis uneven and resultant unnecessary distortion and internal stress as anactuator are considered to impose an unfavorable influence on thereliability of the actuator. Moreover, in the case of FIG. 5B, adistance from the electrode to the plane surface of the conductivepolymer layer sheet is even on the entire area range and is short, whichmakes it possible to apply homogeneous electric fields to the conductivepolymer layer and to perform uniform and high-speed doping of theconductive polymer layer with ion species, which contributes todeformation. In the case of FIG. 5D, on the contrary, a distance fromthe electrode to the plane surface of the conductive polymer layer isuneven, which generates uneven electric fields and uneven doping of ionspecies in accordance with the uneven distance, which limits theoperation speed. It is to be noted that in FIG. 5D, the state beforedeformation is shown by a chain line while the shrunken state afterdeformation is shown by a solid line. Thus, the case of FIG. 5D, thoughit is also the first embodiment of the present invention, is lesspreferable than the case of FIG. 5B.

FIG. 5E is a graph view showing the relationship between the thicknessof the conductive polymer layer and a displacement amount of theactuator of FIG. 5B in the first embodiment of the present inventionwhen a length of the actuator is 8 mm and a film thickness of theelectrode of the actuator is changed (5 μm, 10 μm, 20 μm). Moreover,FIG. 5F is a graph view showing the relationship between a thickness ofthe conductive polymer layer and a growth rate of a displacement amount(displacement growth rate) of the actuator of FIG. 5B in the firstembodiment of the present invention when a length of the actuator is 8mm and a film thickness of the electrode of the actuator is changed (5μm, μm, 20 μm). These graph views show the results of simulation whenassumed values for calculation of the patterned electrode are set asfollows as with the case described before: the material is stainlesssteel SUS304; the longitudinal elastic modulus is 0.072×10¹²N/m²;Poisson's ratio is 0.3; and the thickness is 10 μm, whereas assumedvalues of the conductive polymer layer are set as follows: the materialis polypyrrole; the longitudinal elastic modulus is 0.003×10¹²N/m²;Poisson's ratio is 0.3; and the thickness is 10 μm, 20 μm, 40 μm, 80 μm,and 160 μm. It was discovered that when the thickness of the conductivepolymer layer was 10 μm which was the same as the thickness of theelectrode, the displacement growth rate was 30%, and as the thicknessincreased, the displacement growth rate decreased.

FIG. 5G is a graph view showing the result of FIG. 5F by taking thedisplacement growth rate as a vertical axis and a ratio of thickness ofthe conductive polymer layer to film thickness of the electrode as ahorizontal axis. It was discovered that when said ratio was 3 or less,noticeable displacement increase effect was present.

The displacement increase effect generated in the actuator longitudinaldirection (expansion and contraction direction) in the first embodimentof the present invention is generated in such away that high rigidity inthe width direction orthogonal to the longitudinal direction constrainsthe displacement in this width direction, and distortion componentsunable to escape turn out to join the displacement in the longitudinaldirection of the actuator. The phenomenon of the displacement increaseeffect decreasing as thickness increases is attributable to the factthat as the thickness of the conductive polymer layer becomes largerthan the thickness of the patterned electrode, the distortion componentsare absorbed by a volume potion in the thickness direction so that thecomponents contributing to the displacement in the longitudinaldirection of the actuator decrease. Therefore, the displacement increaseeffect found in the structure of the actuator in the first embodiment ofthe present invention is a characteristic developed particularly anddistinctively in a flat-plate low-profile actuator.

In an actuator which deforms a conductive polymer, the major deformationprinciple is coming and going of anions or cations from and to theconductive polymer layer in an oxidation reduction reaction. Thereforewhen excessive voltage is applied, the electrochemical reaction becomesirreversible, thereby generating defects which affect its cycle life. Itis indicated that the aforementioned displacement increase effect of theactuator in the first embodiment of the present invention allows theactuator to drive at a voltage relatively lower than the actuator whichdoes not have the displacement increase effect, for obtaining the samegenerated displacement. Therefore, the irreversible electrochemicalreaction can be avoided and this particularly is an advantage of theactuator of the present invention, which makes it possible to provide anactuator excellent in cycle life and durability. Similarly, anelectrolyte is dissolved by application of an excessive voltage, andthis affects the life of the actuator. This issue can be solved bydriving at a low voltage.

Further, these apparatuses function by coming and going of anions andcations from and to the conductive polymer layer through voltageapplication, and since this process is a diffusion process, the speed iscontrolled by the diffusion process. By structuring the conductivepolymer layer of the actuator in the first embodiment of the presentinvention to be flat-plate and low-profile, the diffusion is performedswiftly and uniformly in the thickness direction, thereby making itpossible to provide an actuator capable of high-speed function.

Working Example 1

FIG. 6 shows a prototype electrode 1-1 formed by etching a stainlessfoil with a thickness of 10 μm to have a zigzag-shaped electrodepatterning similar to that in FIG. 3A. The dimensions of an elongatedpattern 1 a can be 10 μm width and 14 mm long, with a pitch of 1 mm.Since these zigzag-shaped patterns are extremely thin lines, they haverigidity low enough for them to be deformed by their own weights andlose their shape. Therefore for the purpose of reinforcement, a cutoffportion if is disposed on both sides along the longitudinal direction,and the link portions 1 b of the elongated patterns 1 a and the cutoffportions if are linked by cutoff portion link portions 1 e. As describedlater, these cutoff portions if are cut away at cutting positions 21shown by chain lines in FIG. 6 after the conductive polymer layer 3 isformed on the electrode 1-1. The size of a pattern formation portion ofthe electrode 1 after the cutting is set at 100 mm long and 14 mm wide(corresponding to the length of the aforementioned elongated patterns 1a). On both the end portions of the electrode 1-1, extension portions 1c functioning as a force action portion are provided, and pin holes 1 gfor coupling hooks with pins are provided. Further, on the end portionsof the extension portions 1 c of the electrode 1-1, extractionelectrodes 1 h are further provided. It is to be noted that a small holeand a long hole outside the pin holes 1 g disposed on both the ends areholes disposed for alignment of the pin during manufacturing process.

While formation of the conductive polymer layer 3 on the electrode 1-1can be achieved by electrolytic polymerization or casting method, hereinthe electrolytic polymerization method was employed as a formationmethod for organic conductive polymer. In this case, since theconductive polymer layer 3 was grown by polymerization at locationswhere the electrode of the patterned electrode portion is not present,electrolytic polymerization was conducted while the electrode in FIG. 6was in contact with another stainless flat plate electrode, and then thestainless flat plate electrode was removed. As the conductive polymerlayer 3, polypyrrole with a current density of 1 mA/cm² and a filmthickness of 20 μm was synthesized by electrolytic polymerization in anaqueous solution in which 0.1 mol/liter of pyrrole monomer and 0.25mol/liter of paraphenol sulfonic acid that was to be a supportingelectrolyte layer were dissolved, in a galvanostat mode (constantcurrent control mode) with use of the electrode as a depositionelectrode.

Next, as the electrolyte layer, a polymer gel sheet containing ionicfluid containing butyl methyl imide cation (BMIM⁺) hexa fluorophosphate(PF₆) was bonded to the polypyrrole sheet, and carbon powders weresprayed and applied to the polymer gel sheet as an opposite electrode.

When a voltage of ±1V was applied to the actuator, strain of about 3.5%was observed in the longitudinal direction in an non-load state, andgenerated stress of about 3 Mpa was observed in the state that thedisplacement is constrained. It is to be noted that as a result ofchecking generated displacement in an actuator composed of polypyrroleonly with use of the materials system same as above and without the useof the electrode 1 in the first embodiment of the present invention, thegenerated displacement was about 3%, which confirmed the displacementincrease effect achieved by electrode 1 in the first embodiment of thepresent invention.

In each of the embodiments of the present invention, as the material ofthe electrode 1, metal including gold, platinum, nickel, or titanium;alloy; or carbon, in addition to stainless steel in the above embodimentmay be used. Further, a thin plate made of any one of these materialsmay be coated with these material groups through sputter deposition etc.Further, the surface thereof may be subjected to surface treatment suchas chemical oxidation. Among these materials, a titanium thin plate or asurface coated with titanium through sputter deposition which wassubjected to chemical oxidation treatment with alkali solution such asSCI solution (H₂O₂:NH₃:water=1:1:5) provided particularly good bondstrength with polypyrrole. This chemical oxide film was good inelectrical conductivity with polypyrrole.

In each of the embodiments of the present invention, as the material ofthe conductive polymer layer 3, a pi-conjugated polymer with a basesubstrate of polyaniline, polypyrrole, or polythiophene; any one oforganic conductive polymers which are derivatives thereof; or a carbonconductive polymer such as carbon fine particles, carbon nanotubes, orcarbon fibers are used, by which an actuator involving swell andshrinkage deformation as with the case of the above embodiment may beimplemented.

In each of the embodiments of the present invention, an example offorming an organic conductive polymer layer by casting method isobtained by dissolving powders of polyaniline basic emeraldine(emeraldine base: EB) synthesized by oxidation polymerization in asolvent and spreading the powders and the solvent on a substrate toevaporate the solvent so as to obtain a polyaniline cast film as anorganic conductive polymer layer.

Moreover, an example of forming a carbon dispersion system conductivepolymer layer by a casting method is obtained by mixing carbon fineparticles into a Nafion dispersed solution and spreading the mixture ona substrate to evaporate the solvent.

In each of the embodiments of the present invention, using polymer gelor polymer containing an ionic solution as an electrolyte layer asdescribed in the above embodiment has following advantages. The ionicsolution has a vapor pressure of 1 mHg or lower at ambient temperaturesand is nonvolatile, and therefore the electrolyte layer will not changeby evaporation, allowing long-term usage in the atmosphere withsufficient reliability.

In each of the embodiments of the present invention, as the electrolyteconstituting the electrolyte layer, a fibrous sheet physicallyimpregnated with an electrolyte solvent or an electrolyte solvent beingheld in a polymer gel skeleton may be considered.

The ionic solution is used as the electrolyte, and it is possible toconsider a fibrous sheet physically impregnated with the ionic solutionor the ionic solution being held in a polymer gel skeleton.

In each of the embodiments of the present invention, as the oppositeelectrode, in addition to the carbon powders applied to the actuator inthe above embodiment, a conductive paste or grease containing nonoxidemetal powders of carbon, gold, or the like may be applied thereto.Moreover, a deposited thin film made of metal such as gold, platinum,nickel, or titanium, alloy thereof, or carbon; or the deposited thinfilm so patterned as to decrease rigidity in the longitudinal directionof the actuator may be used.

In each of the embodiments of the present invention, it is naturallyunderstood that a flat plate electrode having a structure identical tothat of the electrode 1 may also be used as the opposite electrode 2.

Second Embodiment

FIG. 7A and FIG. 7B are a plane view and a cross sectional view showinga flat-plate low-profile actuator having a pattern form in anotherelectrode patterning corresponding to second embodiment of the presentinvention. The actuator shown in FIG. 7A and FIG. 7B is identical to theactuator in FIG. 1 in the respect that an electrolyte layer 4 in contactwith the conductive polymer layer 3 is present between an electrode 1-2(corresponding to the electrode 1) having a conductive polymer layer 3and a opposite electrode 2. The electrode 1-2 having the conductivepolymer layer 3 is patterned to have low rigidity in an expansion andcontraction direction 5 of the conductive polymer layer 3, and serves asa planar electrode also functioning as a support. The pattern form inpatterning the electrode 1-2 in FIG. 7A and FIG. 7B is the form in whichmainly in a direction orthogonal to the longitudinal direction 5, anumber of elongated patterns 1 a-2 are disposed and linked through linkportions 1 b. This point is also similar to FIG. 1A, though a basicpattern formed by elongated patterns 1 a-2 is closed like a closedcircuit (in other words, like a square-shaped frame), and these patternsare linked through the link portions 1 b. This structure has theadvantage that if a closed circuit pattern portion 1 a-2 isdisconnected, critical continuity failures of the electrode 1-2 will notoccur unlike the case of the pattern in FIG. 1A.

FIG. 8A and FIG. 8B are a plane view and a cross sectional view showingan actuator having a pattern form in patterning of an electrode 1-3(corresponding to the electrode 1) in another configuration in thesecond embodiment of the present invention. The component members andtheir operations in the drawings are identical to those in FIG. 1A andso the description thereof is omitted. The pattern form in the electrodepatterning is characterized in that the proportion of the link portions1 b to a number of elongated patterns 1 a-3 (corresponding to theelongated patterns 1 a) are further decreased, and closed circuitpattern portions 1 a-3 composed of elongated patterns are increased. Asa result, even if the electrode might be disconnected, the probabilityof critical failure can be further reduced.

FIG. 9A and FIG. 9B are plane views showing an actuator having a patternform in patterning of an electrode 1-4 (corresponding to the electrode1) in still another configuration in the second embodiment of thepresent invention. In FIG. 9A, the width of elongated patterns 1 a-4(corresponding to the elongated patterns 1 a) positioned close toextension portions 1 c (force action portions) of the electrode 1-4 andthe width of link portions 1 b-4 (corresponding to the link portions 1b) are made relatively larger than the width of elongated patterns 1 a-5(corresponding to the elongated patterns 1 a) and the width of linkportions 1 b-5 (corresponding to the link portions 1 b) which are theportions other than the elongated patterns 1 a-4 and the link portions 1b-4 for increasing rigidity in the expansion and contraction direction5. This provides an effect of reinforcing the strength in the locationsclose to the extension portions 1 c (force action portions). FIG. 9Bshows an actuator in a pattern form in patterning of an electrode 1-6(corresponding to the electrode 1) in yet another configuration in thesecond embodiment of the present invention, in which elongated patterns1 a-6 (corresponding to the elongated patterns 1 a) in locations closeto extension portions 1 c (force action portions) and link portions 1b-6 (corresponding to the link portions 1 b) are disposed in a pluralityof lines as with the case in FIG. 9A, so that rigidity in the locationsin the expansion and contraction direction 5 can be increased toreinforce the strength in those locations. Thus, arbitrary distributionof the pattern form in patterning of the electrode 1-6 makes it possibleto impart desirable functions.

Third Embodiment

FIG. 10A, FIG. 10B, FIG. 11A, and FIG. 11B are plane views and crosssectional views respectively showing a stacked actuator in a thirdembodiment of the present invention and a stacked actuator in anotherconfiguration in the third embodiment.

In the actuator shown in FIG. 10A and FIG. 10B, a second conductivepolymer layer integrally formed with a conductive polymer layer 3 on thetop surface of the flat-plate low-profile actuator in the secondembodiment in FIG. 7A with an electrode 1-2 being disposed in a centerportion of the conductive polymer layer 3 and an electrolyte layer andan opposite electrode 2 being disposed on the top surface side of theconductive polymer layer 3 constitutes a flat-plate low-profileconstitutional unit. The flat-plate low-profile constitutional units arestacked in a plurality of layers, e.g., three layers, so that theelectrodes 1-2, the conductive polymer layers 3, the electrolyte layers4, and the opposite electrodes 2 are disposed in parallel with eachother, and one opposite electrode 2 is commonly used for the oppositeelectrode 2 on the lower end of the first-layer actuator and theopposite electrode 2 on the top end of the second-layer actuator, whileone opposite electrode 2 is commonly used for the opposite electrode 2on the lower end of the second-layer actuator and the opposite electrode2 on the top end of the third-layer actuator. Further, a conductive linkmember 13 is interposed in between each extension portion 1 c of thefirst-layer actuator and each extension portion 1 c of the second-layeractuator to establish an electric connection, while a conductive linkmember 13 is interposed in between each extension portion 1 c of thesecond-layer actuator and each extension portion 1 c of the third-layeractuator to establish electric connection. Then, the extension portions1 c of the first-layer actuator to the extension portions 1 c of thethird-layer actuator are hooked by hooks 6, and the hook 6, the hookedextension portion 1 c of the first-layer actuator, upper-side conductivelink member 13, extension portion 1 c of the second-layer actuator,lower-side conductive link member 13, and extension portion 1 c of thethird-layer actuator are pierced by a pin 7, and by linking thesemembers with the pin 7, the load 8 acting upon each extension portion 1c is supported. It is to be noted that reference numeral 12 in FIG. 10Ais a protruding portion protruding from the opposite electrode 2 of thethird-layer actuator along the width direction, and one end of a circuithaving a switch and a power source 9 is connected to the protrudingportion 12 while the other end is connected to the conductive linkmember 13 disposed on either one of the end portions of the actuator.

Moreover, FIG. 11A and FIG. 11B show an actuator in anotherconfiguration. More particularly, in the actuator shown in FIG. 11A andFIG. 11B, a second conductive polymer layer integrally formed with aconductive polymer layer 3 on the top surface of the actuator in thesecond embodiment in FIG. 7A with an electrode 1-2 being disposed in acenter portion of the conductive polymer layer 3 and an electrolytelayer 4 and an opposite electrode 2 being disposed on the top surfaceside of the conductive polymer layer 3 basically constitutes aconstitutional unit. The constitutional units are stacked in a pluralityof layers, e.g., two layers, so that the electrodes 1-2, the conductivepolymer layers 3, the electrolyte layers 4, and the opposite electrodes2 are disposed in parallel with each other, and one opposite electrode 2is commonly used for the opposite electrode 2 on the lower end of theupper-side (second layer in FIG. 11B) actuator and the oppositeelectrode 2 on the top end of the lower-side (third layer in FIG. 11B)actuator. Further, in the uppermost (first layer in FIG. 11B) actuator,the electrolyte layer 4 and the opposite electrode 2 are not disposed onthe upper surface side of the conductive polymer layer 3, while in thelowermost (fourth layer in FIG. 11B) actuator, the electrolyte layer andthe opposite electrode 2 are not disposed on the lower surface side ofthe conductive polymer layer 3. Further, a conductive link member 13 isinterposed in between each extension portion 1 c of the first-layeractuator and each extension portion 1 c of the second-layer actuator toestablish electric connection, a conductive link member 13 is interposedin between each extension portion 1 c of the second-layer actuator andeach extension portion 1 c of the third-layer actuator to establishelectric connection, and further a conductive link member 13 isinterposed in between each extension portion 1 c of the third-layeractuator and each extension portion 1 c of the fourth-layer actuator toestablish electric connection. Then, the extension portions 1 c of thefirst-layer actuator to the extension portions 1 c of the fourth-layeractuator are hooked by hooks 6, and the hook 6, the hooked extensionportion 1 c of the first-layer actuator, upper-side conductive linkmember 13, extension portion 1 c of the second-layer actuator, middleconductive link member 13, extension portion 1 c of the third-layeractuator, lower-side conductive link member 13, and extension portion 1c of the fourth-layer actuator are pierced by a pin 7. By linking thesemembers with the pin 7, the load 8 acting upon each extension portion 1c is supported. It is to be noted that reference numeral 14 in FIG. 11Ais a protruding portion protruding from the lower-side oppositeelectrode 2 of the first-layer actuator along the width direction, andone end of a circuit having a switch 10 and a power source 9 isconnected to the protruding portion 14 while the other end is connectedto the conductive link member 13 disposed on either one of the endportions of the actuator.

In the stacked actuator in the third embodiment and the stacked actuatorin another configuration in the third embodiment, the electrode 1-2 isplanar, and therefore each component member of the actuator is given aplanar structure, which can make stacking easy. The cross sectionalratio of the conductive polymer layer 3 involving the expansion andcontraction action of the stacked actuator allows employment of such aplanar lamination structure, thereby bringing about advantages of easyenhancement of packing density. As a result, it becomes possible toincrease the cross sectional area of the conductive polymer layer 3,which is limited in the case of a single unit, thereby allowingimplementation of an actuator having large generated force necessary inrobotics applications and the like.

It is to be noted that since coming and going of ion species from and tothe conductive polymer layer 3 is a diffusion process, there is atrade-off that time necessary for diffusion can be reduced by decreasingthe thickness of the conductive polymer layer 3. Therefore, it isdesirable to stack a number of conductive polymer layers 3 as a way ofincreasing the cross sectional area.

Fourth Embodiment

Description will be given of a manufacturing method for a planarelectrode support for an actuator in a fourth embodiment, the planarelectrode support functioning as a fundamental member to form theactuators in the first to third embodiments described before.

FIG. 12A, FIG. 12B to FIG. 12H, and FIG. 12I are plane views and crosssectional views showing the planar electrode support structured to haveconductive polymer layer 3 on the electrode 1 and a manufacturing methodtherefor. Since major component members in FIG. 12A and FIG. 12B areidentical to those of the electrode 1 in the flat-plate low-profileactuator described in FIG. 1A (in FIG. 12A, the electrode 1 is hatchedto distinguish the electrode 1 from space portions), the detaileddescription is omitted. Herein, as a component element facilitatingmanufacturing of a planar electrode support 90, a planar electrode 1 isformed to have cutoff portions 1 f, which do not remain as part of theelectrode 1 in the final product, on both the sides in the widthdirection. Respective link portions 1 b for linking a number ofelongated patterns 1 a patterned on the electrode 1 to each other arelinked to each opposed cutoff portion if through cutoff portion linkportions 1 e. Such patterning is performed by etching or punching. FIG.12A and FIG. 12B show the state in which such a planar electrode 1 issupported in close contact with another flat plate 20.

Next, FIG. 12C and FIG. 12D show a state where a conductive polymerlayer 3 is formed so as to cover most parts of the planar electrode 1 inclose contact with the flat plate 20 and the flat plate 20 (in FIG. 12C,the electrode 1 is hatched to distinguish the electrode 1 from spaceportions). In the case of forming the conductive polymer layer 3 throughelectrolytic polymerization, the flat plate 20 serves as a flat plateelectrode, and electrolytic deposition of conductive polymer isconducted by using both the electrode 1 and the flat plate electrode 20as deposition electrodes to form the conductive polymer layer 3 in sucha way as to cover most parts of the electrode 1 and the flat plateelectrode 20. The conductive polymer layer 3 made of polypyrrole in theaforementioned working example 1 was formed by this method. As anotherformation method for the conductive polymer layer 3, a casting methodmay be employed. In this case, the flat plate 20 does not necessarilyneed to be an electrode, and the conductive polymer layer 3 can beformed by such methods as printing or application. One way of formingthe conductive polymer layer 3 by a casting method is dissolving powdersof polyaniline basic emeraldine (emeraldine base: EB) synthesized byoxidation polymerization in a solvent and spreading the powders and thesolvent on a substrate to evaporate the solvent so as to obtain apolyaniline cast film as the conductive polymer layer 3.

Next, after the conductive polymer layer 3 is formed on the flat plate20 so as to cover most parts of the electrode 1, the flat plate 20 isseparated and removed from the electrode 1 and the conductive polymerlayer 3. FIG. 12E and FIG. 12F show a state where the flat plate 20 isremoved from the electrode 1 and the conductive polymer layer 3 in thisway. If necessary, a conductive polymer layer 3 d may be formed on theback surface of the conductive polymer layer 3 as shown in the crosssectional view of FIG. 12G. Thus, forming the conductive polymer layers3, 3 d on the both surfaces of the planar electrode support 90 providesthe advantages that the effective area can be increased and a hole 1 dprovided on the extension portion 1 c that is a force action portion canbe linked through the front and back surfaces to increase reinforcementeffect. Moreover, since the actuator may be structured to be symmetricalwith respect to the planar electrode support 90 as the center, itbecomes possible to provide a planar electrode support 90 equipped withthe conductive polymer layers 3, 3 d, which is free from unbalancedswell and shrinkage actions of the conductive polymer layers 3, 3 d,free from unnecessary bending deformation and allows efficient expansionand contraction deformation in the expansion and contraction direction5.

Finally, at the locations of cutoff lines 21 in FIG. 12E, the cutoffportions 1 f are cut off from both the sides of the planar electrode 1so as to obtain the planar electrode support 90 equipped with theconductive polymer layers 3, 3 d shown in FIG. 12H and FIG. 12I. At thestage that the conductive polymer is formed by electrolyticpolymerization or casting method while the patterned planar electrode 1is in contact with another flat plate 20, the interface between the flatplate 20 and their contact portion is not tightly bonded, and so theflat plate 20 can be easily separated from the electrode 1 and theconductive polymer layer 3. The inventors of the present invention havefurther discovered that easier separation is possible by using a flatplate having a sufficiently smooth surface such as stainless steelplates mirror-finished by buffing for example, or polished glassy carbon(amorphous carbon) plates as the flat plate 20. Particularly, the glassycarbon plate is excellent as it is high in surface hardness, sufficientin chemical stability, and is capable of enduring repeated use.Employing such a manufacturing method allows simplified and easymanufacturing of the planar electrode support for an actuator in thepresent invention.

Further, FIG. 13A and FIG. 13B are a plane view and a cross sectionalview showing a state where a regulating jig is used in the formation ofa conductive polymer layer 3 by electrolytic polymerization, theconductive polymer 3 layer is formed on a substrate 20, and an electrode1 sandwiched by the regulating jig. The regulating jig is composed of abase 31 on which the substrate 20 is placed and a rectangularframe-shaped mask plate 30 placed on the rectangular plate-like base 31and having an aperture window 30 a corresponding to the region in whichthe conductive polymer layer 3 is formed. With use of these, thesubstrate 20 is placed on the base 31 and is covered with the mask plate30, and while the substrate and the electrode 1 which are in closecontact are interposed in between the base 31 and the mask plate 30,screws 32 are inserted into thru-holes of the mask plate 30 and the pinholes 1 g of the electrode 1 on both the end portions and are screwedinto screw holes on the substrate 20 for attachment. When these screwedsubstrate 20 and the electrode 1 are dipped in an electrolyte, portionsof the substrate 20 and the electrode 1 other than the regions which areto constitute the conductive polymer layer 3 are sandwiched between thebase 31 and the mask plate 30, as a result of which the conductivesubstrate 20 and electrode 1 are exposed to the electrolyte only at thelocation of the aperture window 30 a, by which the conductive polymerlayer 3 is synthesized by electrolytic polymerization only at thislocation.

Thus, with respect to the substrate 20 and the electrode 1, the portionsother than the region in which the conductive polymer layer 3 is formed,are covered with the base 31 and the mask plate 30, so that only theregion in which the conductive polymer layer 3 is formed is exposed,allowing the conductive polymer layer 3 in the region to be formedreliably and easily.

Further, FIG. 13C and FIG. 13D show a regulating jig with magnets 33embedded in a base 31A, 31B as another embodiment of the regulating jig.FIG. 13E is a partially enlarged view showing a failure which may occurin the case of using the regulating jig of FIG. 13A and FIG. 13B, inwhich contact between the electrode 1 and the flat plate 20 may be poorenough to generate a gap 34. In the case where such a gap 34 isgenerated, local film defects are likely to be generated when conductivepolymer is formed thereon. To cope with this issue, as shown in FIG.13F, a thin plate made of magnetic materials such as magnetic stainlessmaterials or nickel foils is used as the electrode 1 and the regulatingjig with the magnets 33 embedded therein is used, so that the magnets 33attract the electrode 1 toward the magnet side, which provides an effectof bringing the electrode 1 and the flat plate 20 into close contactwithout any gap. Further, in the case of forming the conductive polymerlayer by electrolytic polymerization, synthesis initiation of theconductive polymer layer occurs with concentrated portions of magneticfields in the vicinity of the magnets as a core, which allows synthesisof an entirely homogeneous conductive polymer layer. As the magneticmaterial of the planar electrode, stainless steel having magnetism suchas SUS430, or nickel can be used as a material noncorrosive in theelectrolyte.

Fifth Embodiment

Examples of applying any one of the actuators in the first to fourthembodiments of the present invention to joint drive mechanism actuators40, 40′ are described as a fifth embodiment of the present invention.FIG. 14A is a side view showing the joint drive mechanism in the fifthembodiment. The joint drive mechanism is structured such that a pair ofthe actuators 40, 40′ are linked across rotatable indirect portions 42of indirect drive mechanisms which are connected through links 41, and apair of these actuators 40, 40′ are driven by antiphase voltages appliedfrom a drive power source 43 to respective electrodes 1 and the like ofthe actuators 40, 40′. As the need arises, a pair of these actuators 40,40′ are antagonistically driven by superimposed bias voltages from thedrive power source 43 applied to the respective electrodes 1 and thelike. Consequently, as shown in FIG. 14B for example, the joint drivemechanism can be driven in such a way that the link 41 is inclinedtoward the right upper side as the conductive polymer layer 3 in theactuator 40 contracts along the longitudinal direction 5 as shown inFIG. 2D while the conductive polymer layer 3 in the actuator 40′ expandsalong the longitudinal direction 5 as shown in FIG. 2B. Conversely, whenvoltages reverse to the above voltages are applied from the drive powersource 43 to the respective electrodes 1 and the like of a pair of theactuators 40, 40′, the joint drive mechanism can be driven in such a waythat the link 41 is inclined toward the right lower side.

Therefore, it becomes possible to provide a joint drive mechanism forrobots which is deformable and provides excellent controllability.

It is to be understood that among the aforementioned variousembodiments, arbitrary embodiments may be properly combined so as toachieve the effects possessed by each embodiment.

Although the present invention has been fully described in connectionwith the preferred embodiments thereof with reference to theaccompanying drawings, it is to be noted that various changes andmodifications are apparent to those skilled in the art. Such changes andmodifications are to be understood as included within the scope of thepresent invention as defined by the appended claims unless they departtherefrom.

INDUSTRIAL APPLICABILITY

The actuator in the present invention is a flat-plate low-profileactuator having an electrolyte layer in contact with a planar conductivepolymer layer disposed in between an electrode having the conductivepolymer layer attached thereto and an opposite electrode, for deformingthe conductive polymer layer to be swelled and shrunken by applicationof electric fields to between both electrodes, in which the electrodehaving the conductive polymer layer attached thereto is a planarelectrode also serving as a support, which is patterned so that rigidityin a longitudinal direction that is an expansion and contractiondirection of the conductive polymer layer is low while rigidity in awidth direction almost orthogonal to the longitudinal direction is high.The actuator is usable as a drive source of various apparatuses such asrobots which are expected to operate near the presence of human beingsfor housekeeping assistance, job assistance, and nursing help forelderly and physically-challenged persons in homes, offices, andhospitals, and as a flat-plate low-profile actuator in which the drivesource itself is small-size, light-weighted, and flexible as well safe.

1-15. (canceled)
 16. A manufacturing method for a planar electrodesupport for a flat-plate low-profile actuator, in which the flat-platelow-profile actuator has an electrolyte layer in contact with aconductive polymer layer disposed in between an electrode having theplanar conductive polymer layer attached thereto and an oppositeelectrode for deforming the conductive polymer layer to be swelled andshrunken by application of electric fields to between both electrodes,and the planar electrode support is composed of the conductive polymerlayer and the electrodes, comprising: patterning a planar electrode asthe electrode through etching or punching to have at least one bentportion along a longitudinal direction that is an expansion andcontraction direction of the conductive polymer layer so that rigidityin the longitudinal direction is low while rigidity in a width directionalmost orthogonal to the longitudinal direction is high; and in a statethat the patterned planar electrode is in contact with another flatplate, forming the conductive polymer layer on the electrode byelectrolytic polymerization or casting method, and then removing theflat plate to manufacture the planar electrode support.
 17. Themanufacturing method for a planar electrode support for a flat-platelow-profile actuator as defined in claim 16, wherein the conductivepolymer layer is further formed, by electrolytic polymerization orcasting, on a surface with the flat plate being removed to manufacturethe planar electrode support.
 18. The manufacturing method for a planarelectrode support for a flat-plate low-profile actuator as defined inclaim 16, wherein in a state that the planar electrode to make theelectrode is linked to a cutoff portion, which will not remain as theelectrode, through a cutoff portion link portion, the conductive polymerlayer is formed on the electrode by electrolytic polymerization orcasting and then the cutoff portion is removed by cutting at the cutoffportion link portion to manufacture the planar electrode support. 19.The manufacturing method for a planar electrode support for a flat-platelow-profile actuator as defined in claim 16, wherein the planarelectrode to make the electrode is a magnetic substance, and theelectrode made of the magnetic substance is brought into contact withthe another flat plate through attraction by magnetic force.